The objective of this study is to measure permanent tooth loss and the factors which influence it. The study was conducted in two phases. The first phase is independent of the second and is a complete study without the second phase. Specific aims of Phase I are to describe the: (1) biological condition of extracted teeth, (2) sociodemographic, attitudinal, economic, and care-seeking characteristics of individuals who have extractions, and (3) selected characteristics of the dental providers who perform the extractions. Phase II was conducted after the first phase and collected information on patients whose teeth were treated with dental services that are alternatives to extraction for given biological conditions. These teeth will be controls for the extracted teeth and will allow the estimation of a model which explains the factors which influence the choice between extraction and its alternatives. The same dental practices were used for both phases. Data from both Phases will be used to develop a more complete explanation of the relative significance of a multiplicity of factors for tooth loss. Phase I of the project has been completed and data collection for Phase II is nearing completion. Some aspects of the Phase II protocol were redesigned based on Phase I experience. Chief among the modifications: a new set of extraction patients were enrolled into the study, eligibility criteria were based on the treatments patients received, revised data collection forms (and the addition of a new log form to collect information about all patients seen by the participating dentist), two new procedures manuals, revised sampling strategy for dentists and patients, and a revised number of patients each dentist was expected to enroll into the study. The new protocol is more complex than that used to guide Phase I or intended for Phase II; increased training and monitoring/support from the program office in each site, however, has ensured high quality data collection.